Court update
As you say, all will be revealed in due course. I do however know my source personally so I'm comfortable it's accurate.
With regard to numbers, BASSA are praying that the number of volunteers is low. This is obviously part of their bullying tactics towards pilots in the hope some might decide against it as a result. BA are quite rightly keeping their cards close to their chests but bearing in mind there has been a very strong response to the request for volunteers, I think its important BASSA are aware of the strength of feeling against them and their outdated tactics. More importantly, crew still planning on striking need to know they'll be standing on a picket line or watching on Sky News as a steady stream of British Airways aircraft take-off from Heathrow.
Volunteers with previous crew experience are being rostered as SCCMs because it alows BA to have some assurity they can operate these services without relying on CSDs and Pursers working. Those CSDs and Pursers already telling BA they will work during a strike are of course also being rostered to work during the planned strike period. BA does need to have nominated SCCMs on passenger services and it can't use existing main crew to fulfill this on a planned basis. I assume it also doesn't want to put added pressure on main crew already working in difficult circumstances, whereas we are old enough and ugly enough to look after ourselves!